JP2005036781A - Method of manufacturing fuel distribution pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel distribution pipe and a method of manufacturing the fuel distribution pipe capable of eliminating the occurrence of burrs at a contact part between the fuel passage and the fuel supply port of the fuel distribution pipe, minimizing a time required for manufacture by sufficiently distributing a molten metal into a cavity, and preventing pores and shrinkage from occurring. <P>SOLUTION: In this fuel distribution pipe, a sloped surface is provided on the closed wall of the fuel distribution pipe in which a fuel passage is formed along the longitudinal axis thereof, one end is opened and the other end comprises the closed wall, and a mounting hole for a fuel injection valve is formed along the longitudinal axis thereof. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel distribution pipe manufacturing method, and more particularly to a fuel distribution pipe manufacturing method for supplying fuel supplied from a fuel pump to each intake passage or each cylinder of an engine via a fuel injection valve.

  Conventionally, it is described in Patent Document 1 shown below. As shown in FIG. 10 (FIG. 1 of Patent Document 1), the fuel distribution pipe 1 is made of a synthetic resin in which one end 1A on the right is opened and a fuel chamber F is formed. The axial center line XX extends in the horizontal direction in FIG. The fuel chamber F also extends along the longitudinal axis XX. The fuel distribution pipe 1 is provided with a plurality of fuel injection valve mounting holes 2 that open to the fuel chamber F along the longitudinal axis XX, and the fuel injection valve mounting hole 2 has a fuel injection valve. Is attached.

  The fuel distribution pipe 1 is formed by injection molding a synthetic resin material. In FIG. 11 (FIG. 2 of Patent Document 1), the fixed mold 10 is fixed to a molding machine, and the outer portion of the upper half of the fuel distribution pipe 1 is engraved on the mold mating surface. The outer portion of the upper half means the outer portion above XX in FIG. The movable mold 11 is moved by a molding machine and is configured to abut against and separate from the fixed mold 10, and an outer portion of the lower half of the fuel distribution pipe 1 is engraved on the mold mating surface N. The outer portion of the lower half means the outer portion below the line XX in FIG. The fixed mold 10 and the movable mold 11 abut against the mold mating surface N, and the shape of the outer portion of the fuel distribution pipe 1 is defined between the molds 10 and 11 by this abutment. The movable core 12 is located between the mating surfaces N of the fixed mold 10 and the movable mold 11, and advances and retreats into the outer portion of the fuel distribution pipe 1 formed by the fixed mold 10 and the movable mold 11. It is arranged so as to be freely movable to the right in FIG.

The cavities are formed as shown in FIG. The injection gate passage 13 for injecting into the cavity is disposed at a position satisfying the following conditions (1) and (2).
(1) As shown in FIG. 12 (FIG. 6 of Patent Document 1), it passes through the centers C1, C2, C3 of the cross section of the plurality of fuel injection valve mounting holes 2 that open to the fuel chamber F of the fuel distribution pipe 1. It lies on a line segment YY extending along the longitudinal axis XX of the fuel distribution pipe 1.
(2) Located in the outer portion of the fuel distribution pipe 1 on the side facing the fuel injection valve mounting hole 2 that opens to the fuel chamber F of the fuel distribution pipe 1.

  In FIG. 10, the movable core 12 receives the injection pressure of the molten synthetic resin material injected from the injection gate passage 13 from above, so that the movable core 12 is pressed downward, and the lower part of the movable core 12 Is strongly pressed by the protrusion B corresponding to the tip opening of the fuel injection valve mounting hole 2 formed in the movable mold 11.

  In such a state, the molten synthetic resin is filled in the cavitation and the injection of the synthetic resin into the cavitation is stopped. After cooling and solidification are completed in this state, the movable mold 11 and the movable core 12 are completed. Is separated from the fixed mold 10 and the product is taken out from the mold. FIG. 13 (FIG. 4 of Patent Document 1) shows the completed state of the fuel distribution pipe 1 from which the product has been taken out from the mold.

    Japanese Patent Laid-Open No. 5-44594 (page 3, FIG. 1, FIG. 2, FIG. 4, FIG. 6)

  The problem to be solved is that, in the apparatus of Patent Document 1, generally, the fuel distribution pipe has a large aspect ratio, and if there is an injection gate in a direction perpendicular to the longitudinal axis, the molten metal travels around the outer periphery of the movable core. Since the protrusion corresponding to the tip opening of the injection valve mounting hole is pressed, the molten metal collides and the movable core rises due to the reaction of the pressure, and there is a risk that flash will occur. In addition, since the lower portion of the movable core strongly presses against the protruding portion corresponding to the tip opening of the fuel injection valve mounting hole formed in the movable mold, no gap is generated in the contact portion. Since the flow direction of the injected molten metal is bent in a right-angled direction and moved a long distance in the left-right direction, there is a problem that the molten metal is not easily filled to the end of the cavity and a nest or sink is easily formed.

  Therefore, the present invention eliminates the generation of flash at the contact portion between the fuel passage and the fuel supply port of the fuel distribution pipe, and also shortens the time required for manufacturing as much as possible, and further eliminates the occurrence of nests and sink marks. An object is to provide a manufacturing method.

  In order to achieve the above-mentioned object, the invention described in claim 1 is characterized in that a fuel passage is formed in the interior along the longitudinal axis thereof, one end is opened, the other end is provided with a closed wall, and the longitudinal direction is provided. In the method of manufacturing a fuel distribution pipe in which a mounting hole of a fuel injection valve opens into the fuel passage along an axis, the inclined wall is provided on the closing wall, and an injection gate is provided on the inclined surface of the closing wall of the fuel distribution pipe. It is intended to be provided at a position opposite to.

  According to the first aspect of the present invention, the molten synthetic resin material injected from the injection gate moves along the longitudinal axis XX through the inclined surface side without largely changing the injection direction. Then, the molten metal reaches the protruding portion. Also, when the molten synthetic resin material injected from the injection gate collides with the inclined surface of the slide core, the slide core bends by its component force, and the outer peripheral surface of the slide core and the protruding portion are in close contact with each other and come into contact with each other. Eliminate gaps between parts.

  Invention of Claim 2 is a manufacturing method of the fuel distribution pipe of Claim 1, Comprising: A part of opening of the said injection gate exists in the range from the start point of the said inclined surface to an end point. Is the main point. According to the structure of the said invention, there exists an effect similar to Claim 1.

  Invention of Claim 3 is a manufacturing method of the fuel distribution pipe of Claim 1, Comprising: All the opening of the said injection gate exists in the range from the start point of the said inclined surface to an end point. The main purpose. According to the structure of the said invention, there exists an effect similar to Claim 1.

  As an effect of the above invention, according to the configuration of the invention described in claims 1, 2 and 3, it is possible to prevent the occurrence of flashes, nests, sink marks and the like.

  Embodiment 1 of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view of a fuel distribution pipe, and FIG. 2 is a longitudinal sectional view taken along line AA in FIG. In the description, upper, lower, left, and right are shown in the drawings and are not limited thereto. The fuel distribution pipe 1 has a fuel passage 2 formed therein, an opening 3 formed at one end, and a closing wall 4 formed at the other end, and is formed of a synthetic resin material. The fuel distribution pipe 1 extends in the horizontal direction along the longitudinal axis XX. Similarly, the fuel passage 2 extends along the longitudinal axis XX. In this embodiment, the ratio of the outer diameter dimension to the length in the longitudinal direction, that is, the aspect ratio is about 1:20. An inclined surface 4c is provided on the upper portion of the closing wall 4, and the inclined surface 4c exists between the start point 4a and the end point 4b.

  The fuel distribution pipe 1 is provided with a plurality of fuel injection valve mounting holes 5 along the longitudinal axis XX, and communicates with the fuel passage 2 through the fuel supply port 6. A fuel injection valve (not shown) is attached to the attachment hole 5. As shown in FIG. 2, the cross-sectional shape of the fuel passage 2 has a tunnel shape in which the upper part is an arc and the lower part is a plane. The opening 3 of the fuel distribution pipe 1 is sealed by a stopper (not shown) or a pressure regulator (not shown).

  The fuel passage 2 is supplied with high-pressure fuel from a fuel pump (not shown) driven by an electric motor, and the high-pressure fuel injected from the fuel injection valve is controlled by an electronic control unit so that the cylinder of the engine It is injected toward the inside or intake port. The electronic control device includes an MPU, a RAM, a ROM, an I / O interface, and the like. The fuel distribution pipe 1 is formed as described above, and is formed by injection molding a synthetic resin material. The plurality of attachment portions 7 are formed integrally with the main body of the fuel distribution pipe 1, and are fixed to the intake pipe or the engine block by bolts. The number of mounting holes 5 of the fuel injection valve and mounting portions 7 of the fuel distribution pipe 1 can be changed according to the number of cylinders of the engine.

  Next, a mold for forming the fuel distribution pipe 1 will be described in detail with reference to FIGS. 3 is an assembly drawing of the mold, FIG. 4 is a longitudinal sectional view taken along line BB in FIG. 3, FIG. 5 is a partially enlarged sectional view of FIG. 1, and FIG. It is a longitudinal cross-sectional view. The mold 10 is formed by combining a fixed mold 11 and a movable mold 12. The fixed mold 11 is fixed to an injection molding machine (not shown), and an outer portion of the upper half of the fuel distribution pipe 1 is engraved on the mold matching surface 13. In addition, the outer part of the upper half means the outer part above the longitudinal axis X-X line shown in FIG.

  The movable mold 12 is moved by the injection molding machine so as to come into contact with and away from the fixed mold 11, and the outer side portion of the lower half of the fuel distribution pipe 1 is engraved on the mold matching surface 13. The outer part of the lower half means the outer part below the longitudinal axis XX shown in FIG. The fixed mold 11 and the movable mold 12 are brought into contact with each other at the mold mating surface 13 so that the shape of the outer portion of the fuel distribution pipe 1 between the molds 11 and 12, that is, the upper part and the lower part are matched. The shape is defined.

  The slide core 14 can freely advance and retreat into the outer portion of the fuel distribution pipe 1 formed by the fixed mold 11 and the movable mold 12. In FIG. 3, the cylinder can be moved by a hydraulic cylinder (not shown) until it abuts on the step 11 a of the fixed mold 11 and the step 12 a of the movable mold 12. An inclined surface 16 is formed on the top end portion 15 of the slide core 14. As shown in FIG. 4, the cross section of the slide core 14 is such that the upper portion 14a is an arc and the lower portion 14b is a plane. A movable core 17 that molds the mounting hole 5 to which the fuel injection valve is mounted is provided at a plurality of locations, and can be moved in the vertical direction by a hydraulic cylinder (not shown), and the movable mold 12 is in contact with the stepped portion 12b. The protruding portion 18 protrudes into the space. The outer diameter of the protrusion 18 of the movable core 17 is smaller than the outer diameter of the main body 19.

  An injection gate 21 for injecting the molten synthetic resin material into the cavity 20 at a high pressure opens to a side surface 22 corresponding to the closing wall 4 of the fuel distribution pipe 1 formed by both molds 11 and 12. It is provided along the longitudinal axis XX. As shown in FIG. 5, the injection gate 21 is engraved in the fixed mold 11 with respect to the mold matching surface 13. The inclined surface 16 of the slide core 14 is provided between the start point 16 a and the end point 16 b above the die-matching surface 13 of the fixed mold 11. Therefore, a part of the opening 21 a of the injection gate 21 is hung on the inclined surface 16.

  Next, the injection molding method will be described in detail with reference to FIGS. Before the injection, the movable mold 12 is separated from the fixed mold 11. The movable mold 12 is moved upward by a hydraulic cylinder (not shown) by the starting operation and is brought into contact with the fixed mold 11. Next, the slide core 14 is moved from the right direction to the left direction by the hydraulic cylinder, and comes into contact with the step portions 11a and 12a and stops. Subsequently, the movable core 17 is moved upward from below by a hydraulic cylinder (not shown), so that a cavity 20 indicating the outer shape of the fuel distribution pipe 1 is formed in the mold 10 as shown in FIG. Is done. Depending on the processing accuracy of the mold 10, the slide core 14, and the movable core 17, the protruding portion 18 of the movable core 17 may come into contact with the lower surface of the slide core 14 or a slight gap may occur. This contact portion is referred to as a contact portion.

  Then, the synthetic resin material melted through the injection gate 21 in a state where mold matching is completed is injected into the cavity 20 at a high pressure. A molten synthetic resin material injected at a high pressure from the injection gate 21 collides with the inclined surface 16 of the slide core 14. As a result, a part flows into the lower part 20b of the cavity 20, but a majority flows into the upper part 20a. A thick arrow indicates a large amount of the synthetic resin material, and a thin arrow indicates a small amount of the synthetic resin material. The slide core 14 is pressed and bent downward by the component of the injection pressure, and the lower portion 14b of the slide core 14 strongly presses the flat surface 18a of the projecting portion 18 of the movable core 17. As a result, the plane of the lower portion 14b of the slide core 14 and the plane 18a of the protruding portion 18 are in close contact with each other, so that no gap is formed. Further, the molten synthetic resin material injected at the same time moves quickly along the longitudinal axis XX without largely changing the injection direction, and after filling the upper portion 20a of the cavity 20 first. Since the lower portion 20b of the cavity 20 is filled, the slide core 14 quickly reaches the entire area of the cavity 20 without being lifted. As a result, the synthetic resin material does not enter the contact portion, and no flash is generated.

  After the synthetic resin material is cooled and solidified, the movable core 17 is moved downward by the hydraulic cylinder, and then the slide core 14 is moved rightward. Then, when the movable mold 12 is separated from the fixed mold 11, it is transferred to the shape as shown in FIG. Since the injection gate 23 remains in the molded product, the finished product is obtained by cutting. The reason why the movable core 17 is movable is to prevent wear caused by repeated sliding of the lower portion 14b of the slide core 14 and the protrusion 18 of the movable core 17 when the movable core 17 is fixed. It is. When the distance between the opening 21a of the injection gate 21 and the mounting hole 5 is long, the filling speed of the synthetic resin material is slow at the start of filling, and thereafter, it is preferable to increase the speed from the medium speed to the high speed because the synthetic resin material spreads throughout. .

  As described above, according to the fuel distribution pipe of the first embodiment described above, when the injection pressure of the molten synthetic resin collides with the inclined surface 16 of the slide core 14, the component of the injection pressure causes the slide core 14 to move toward the movable core 17. Is pressed strongly against the flat surface 18a of the projecting portion 18 of the movable core 17, so that the flat surface 14b of the slide core 14 and the flat surface 18a of the projecting portion 18 of the movable core 17 are in close contact with each other. The gap is eliminated by contact, and the synthetic resin material does not enter the gap of the contact portion. Therefore, the occurrence of flash is prevented. Furthermore, the simultaneously injected synthetic resin material flows quickly along the longitudinal axis XX without largely changing the injection direction, and first fills the upper portion 20a of the cavity 20 and then continues to the cavity 20 Since the lower portion 20b is filled, the slide core 14 is prevented from being lifted, and it is difficult to cause flash, nests and sink marks.

  FIG. 7 shows a second embodiment in which the position of the injection gate is different from the first embodiment. About 1/2 of the injection gate 24 is engraved on the mold matching surface 13. When the molds are matched, the injection gate 24 is formed. The inclined surface 16 of the slide core 14 is provided on the upper side of the mold matching surface 13 as in the first embodiment. As a result, a part of the opening 24 a of the injection gate 24 is hooked on the inclined surface 16.

  Next, the operation will be described. When high pressure molten synthetic resin material is injected from the injection gate 24, it collides with the tip 15 of the slide core 14 and a part flows into the lower part 20 b of the cavity 20. It flows into the upper part 20a of the cavity 20 from the point 16a. Therefore, there is an effect similar to that of the first embodiment.

  FIG. 8 shows a third embodiment in which the position of the inclined surface is different from the second embodiment. About 1/2 of the injection gate 24 is carved into the mold matching surface 13, and the injection gate 24 is formed when mold matching is performed. The inclined surface 25 is provided from the start point 25 a of the lower part 20 b of the cavity 20 to the end point 25 b of the upper part 20 a of the cavity 20. The opening 24 a of the injection gate 24 is opened in the inclined surface 25.

  Next, the operation will be described. When high pressure molten synthetic resin material is injected from the injection gate 24, a part of the plastic resin collides with the tip 15 of the slide core 14 and flows into the lower part 20 b of the cavity 20. It flows into the upper part 20a of the cavity 20 from the starting point 25a. Therefore, there is an effect similar to that of the first embodiment.

  Example 4 in which the positions of the inclined surfaces of the injection gate and the slide core are different is shown in FIG. The injection gate 26 is carved into the mold matching surface 13 on the movable mold 12 side, and the injection gate 26 is formed by combining with the fixed mold 11. The inclined surface 25 is the same as that of the third embodiment. It is provided from the start point 25 a of the lower part 20 b of the cavity 20 to the end point 25 b of the upper part 20 a of the cavity 20. A part of the injected synthetic resin material collides with the tip portion 15 and flows into the lower portion 20b of the cavity 20, but most of it flows into the upper portion 20a on the inclined surface 25. There are effects similar to those of the first embodiment.

  The embodiment described above is not limited to this, and can be modified as follows without departing from the scope of the claims. For example, although the inclined surface of the slide core is a flat surface, it may be a circular or spherical concave surface or convex surface. As a result, since the injection pressure of the synthetic resin material to be melted acts more strongly than when it is flat, the pressing force to the protrusion is further increased than when it is flat, and the occurrence of flash is further reduced. Moreover, although the cross-sectional shape of the injection gate is a rectangle, it may be a circle, a semicircle, a triangle, a trapezoid, or the like. The abutting portions between the lower portion of the slide core and the projecting portion of the movable core are flat surfaces, but may be arcs. As a result, the slide core and the movable core are brought into close contact with each other without being laterally displaced, so that the occurrence of flash is eliminated and precise injection molding can be performed. The cross-sectional shape of the injection gate can be determined by the shape of the fuel distribution pipe.

  As an application example of the present invention, it can be applied not only to injection molding of synthetic resin materials but also to die casting of aluminum or magnesium.

  1 is a longitudinal sectional view of a fuel distribution pipe according to Embodiment 1. FIG.   It is a longitudinal cross-sectional view along the AA line of FIG.   It is an assembly drawing of a mold.   It is a longitudinal cross-sectional view along the BB line of FIG.   3 is a partially enlarged cross-sectional view of Example 1. FIG.   It is a longitudinal cross-sectional view of the fuel distribution pipe at the time of completion of injection molding.   6 is a partially enlarged cross-sectional view of Example 2. FIG.   10 is a partially enlarged cross-sectional view of Example 3. FIG.   10 is a partially enlarged cross-sectional view of Example 4. FIG.   It is a longitudinal cross-sectional view of the fuel distribution pipe which shows the former.   It is a metal mold | assembly figure for injection molding the fuel distribution piping which shows the former.   It is a longitudinal cross-sectional view of the fuel distribution pipe after the completion of injection showing the conventional.   It is a top view of FIG.

Explanation of symbols

1: Fuel distribution pipe 2: Fuel passage 4: Closing wall 4c: Inclined surface 5: Mounting hole 10: Mold 11: Fixed mold 12: Movable mold 14: Slide core 16, 25: Inclined surfaces 16a, 25a: Start Points 16b, 25b: End point 18: Protruding portions 21, 24, 26: Injection gate

Claims (3)

A fuel passage is formed in the inside along the longitudinal axis, and one end is open, and the other end is provided with a closing wall, and a mounting hole for a fuel injection valve is formed in the fuel passage along the longitudinal axis. In the manufacturing method of the fuel distribution pipe that opens,
The said closed wall is provided with the inclined surface, The injection gate is provided in the position facing the inclined surface of the said closed wall of the said fuel distribution pipe, The manufacturing method of the fuel distribution pipe characterized by the above-mentioned.   2. The fuel distribution pipe manufacturing method according to claim 1, wherein a part of the opening of the injection gate is in a range from a start point to an end point of the inclined surface.   2. The fuel distribution pipe manufacturing method according to claim 1, wherein all the openings of the injection gate are within a range from a start point to an end point of the inclined surface.

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